The purpose of this project is to develop novel cell-selective therapeutic targeting agents for treating bladder cancer. Making use of two non-overlapping phage-display derived bladder cancer-specific binding peptides (BCSBPs) already developed, conjugates will be created between these BCSBPs and both an active chemotherapeutic drug (Epirubicin) and two biologic proteins (cytokines IL-2 and IL-12). Binding and functional activity of these BCSBPs will be optimized against a mouse bladder cancer cell line previously shown to share the same binding characteristics for these BCSBPs as multiple human bladder cancer cell lines. The long-term goal is to develop the necessary methodology for translating these targeting motifs into clinical use immunotherapeutic against human bladder cancer. Towards achieving these goals, two specific aims will be undertaken: Specific Aim 1: To chemically conjugate BCSBPs with the chemotherapeutic drug Epirubicin, and to assess cytotoxicity of the conjugates in targeting bladder cancer cells. The conjugates will be made through a chemical coupling process that explores positional effects, number of targeting motifs and use of spacers to achieve maximal binding specificity, affinity, and functional cytotoxic activity. Specific aim 2: To genetically conjugate BCSBPs with Thl cytokines IL-2 and IL-12, and to assess the binding and biological activities of these fusion proteins upon targeted bladder cancer cells. These fusion proteins will be made using prokaryotic or insect expression systems. Binding specificity will be optimized using a GFP-conjugate prototype. Biological activity for IL-2 and IL-12, alone and as synergistic agents will be tested using well-established bioassays. Successful completion of this study will result in future pre-clinical studies using these novel therapeutic conjugates in animal bladder cancer models that may further lead to a quick translation of this strategy into a clinically useful treatment modality for human bladder cancer.